A–C, Surgical planning, case 9 (Table 1): 18-year-old boy with life-long medically intractable seizure disorder due to a perinatal hemorrhage (A). A–C, Surgical planning, case 9 (Table 1): 18-year-old boy with life-long medically intractable seizure disorder due to a perinatal hemorrhage (A). The patient had a spastic right hemiparesis but retained some right-hand function. Owing to the perceived proximity of the left frontal encephalomalacic cyst to the anatomic central sulcus, and the fact that the injury occurred in the perinatal period, the possibility of functional cortical reorganization was considered. Scalp EEG recordings revealed the site of seizure onset to be near the posterior margin of the cyst. Functional MR imaging was performed (B) to clarify the relationship between the functional sensorimotor area and the posterior margin of the cyst. Results of this study were used to guide surgical placement of EEG strips to ensure the functional hand area was covered by the subdural strips for purposes of extraoperative cortical stimulation mapping. The collage in C represents a 3D rendering of the brain with the functional MR imaging activation (red) embedded (on the reader's left). The orientation of the 3D rendering is identical to that of the exposed surgical field (on the reader's right), with the patient's nose toward the top of the page, the back of the head toward the bottom of the page, superior to the reader's right and inferior to the reader's left. Extraoperative ictal video-EEG recording and cortical stimulation mapping revealed that the functional hand area was located beneath the three electrode contacts to the left of the “T” of the more posterior strip, which coincided with the functional MR imaging study. The area of ictal onset was located beneath the three most cephalic electrodes to the right of the “T” of the more anteriorly positioned strip. The epileptogenic zone was resected and the patient has been seizure-free for over 2½ years Christine C. Lee et al. AJNR Am J Neuroradiol 1999;20:1511-1519 ©1999 by American Society of Neuroradiology